Mohamad-Ziad Charif - Antares

a look at figure 5.22 we find a clear pattern where if the mass of the WIMP isheavier the higher fraction of the signal is concentrated at small ∆(Ψ) values.This is simply due to the fact that the heavier the WIMP is, more energetic theneutrinos can be and in consequence they have better angular resolution. Thesame effect can be noticed when looking at different annihilation channels as theb + b − channel is softer than W + W − or τ + τ − . Looking again in figure 5.22 we cansee that the signal for 500 GeV τ + τ − is concentrated at even lower ∆(Ψ) valuesthan the signal for 1000 GeV b + b − , the simple reason is that the former simplyannihilates on average into higher energetic neutrinos than the latter even thoughit is twice as heavy. This leads us to two predictions:1. For the same annihilation channel we would expect to find a anti-correlationbetween optimized ∆(Ψ) cut and the WIMP mass, the heavier the WIMPthe smaller the ∆(Ψ) cut should be.2. For the same WIMP mass we would expect to see lower ∆(Ψ) cuts for τ + τ −and W + W − (with almost no difference between them) when compared tothe b + b − annihilation channel.These two predictions are confirmed when looking at the final values of the optimized∆(Ψ) cuts seen in figure 5.23.Figure 5.21: Percentage of difference among optimized sensitivity ¯Φ 90% and thebest value ( χ 2 < 1.6)with as a function of the χ 2 cut.98